Diddy, Girlfriend Kim Porter Break Up

It's over between Sean "Diddy" Combs and his girlfriend of 10 years, Kim Porter, a rep for Combs confirms to PEOPLE.

A source close to Porter says she has moved out of the apartment she shared with Combs, and into a new home in Los Angeles with her children.

The New York Post's Page Six column reported last week that Porter had moved out of Diddy's New York City apartment and bought a home in Beverly Hills.

On Wednesday Porter issued a statement saying, "In ending this relationship, I made a decision that was in the best interest of myself, Sean and our family. I look forward to moving on with my life and my career, and wish him prosperity, health and happiness in life and in love. We will remain friends and committed parents to our children."

A source close to Diddy says "he's really saddened by the loss. [Kim] has been a part of his life for a long time. It's like losing his best friend."

A rep for Diddy denied the Post's report that the mogul's relationship with actress Sienna Miller caused a rift with Porter.

"There is literally nothing between them," the rep told PEOPLE last week. A rep for Miller also said that "reports of Sienna being linked with P. Diddy are categorically untrue."

Porter, 36, and Diddy, 37, are parents to son Christian, 9, and twin daughters D'Lila Star and Jessie James, born Dec. 21. Combs also has another son, Justin, 13, with stylist Misa Hylton-Brim; Porter has a teenage son, Quincy, with singer Al B. Sure.

The couple, who began dating in the '90s, have shared a tempestuous history. They broke up in 1999 and battled in court over child support for Christian; Combs also dated Jennifer Lopez for two years before he and Porter reconciled in 2003.

Still, Combs told Essence in its December issue that he had no plans to marry Porter. "I know she deserves to get married, but I'm just not ready," he said. "It's not a reflection on how much I love Kim. It's that I'm just learning how to be a good boyfriend. When I'm finished with this step, I'll move on to the next."

In that same interview, Porter praised Combs as a father and provider, saying, "He could be a little more attentive to his family, but I understand who he is and what that requires of him. He's in a business where he wants to be the best, and he wants to make sure his family has the best."